The classic mistake people make when judging how a hockey game should work out is to measure team strength as good team/bad team. The bad team is bad up and down the lineup and perform poorly at everything. The good team is the opposite. This leads people to think a team can’t be good if it’s bad at some things or that a team can’t be good at some things if it’s bad. When the Leafs play the Senators, you should be able to see how wrong both of those ideas are just by watching.
When you run their actual lineups plus their results this season through a model (this one is Moneypuck’s) and then tweak it with home ice advantage, the Leafs are 54% favourties to win to the Sens 46%.